1. Field of the Invention
This invention pertains to differential systems for motor vehicles and, more particularly, the invention pertains to a device and method for adjusting an axle shaft endplay in a differential assembly.
2. Description of the Prior Art
In conventional drivelines, particularly those for rear wheel drive vehicles, the left-hand and right-hand axle shafts extend laterally from a differential mechanism that includes side bevel gears in continuous meshing engagement with differential pinions supported rotatably on a pinion shaft carried on a differential carrier. The differential carrier is driven rotatably by a set of meshing bevel gears, one of which is driven by a drive shaft disposed substantially perpendicular to the axle shafts. The side bevel gears typically are connected rotatably to the axle shafts by a spline connection formed on a shoulder near the inboard ends of the axle shafts. Each axle shaft carries a terminal shoulder at its axially innermost extremity, the terminal shoulder is located adjacent to the differential pinion shaft.
Located between the shoulders on the axle shaft is an annular recess that is axially aligned with the recess formed on the corresponding side bevel gear. A slotted washer or retainer ring, fitted within the recesses of the axle shaft and side bevel gear, limits outward axial movement of the axle shaft relative to the side bevel gear. However, each axle shaft is free to move along the spline connection axially inward toward the differential pinion shaft. This amount of an internal axial clearance is called an axle shaft endplay.
The excessive amount of the endplay in the differential assemblies allows the axle shafts to shift axially inwardly relative to the differential case and jar or knock against the pinion shaft. Moreover, the conventional assembly can lead to grinding away of the end of the side yoke causing excessive negative camber, which in turn can lead to uneven tire wear and poor driving stability. It can also cause particles of the side yokes to embed themselves in the differential clutch plates causing slippage of the differential unit resulting in a clunking or thumping noise. If the wear is left unchecked, it may increase to a point where the flange will shear or cut into the differential case causing a leakage of fluid and ultimately leading to complete destruction of the differential assembly.
The current retention method of the axle shaft does not allow an endplay control. Therefore, the need exists to control the endplay of the axle shaft in order to provide a predetermined desired endplay in accordance with vehicle manufacturer""s specification and/or depending on the operational conditions of the axle assembly in a simple, efficient and inexpensive manner.
It is an object of the present invention to provide a device and a method for adjusting an axle shaft endplay in a differential assembly.
A device, according to the present invention, for adjusting an endplay of an axle shaft in a differential assembly includes an axle shaft supported in a differential case for rotation about a longitudinal axis, and an endplay adjustment member. The axle shaft has external splines adapted to mate with internal splines of a differential side gear and an annular groove located adjacent to a terminal shoulder provided at an inboard end of the axle shaft. The annular groove receives a retainer ring provided to limit an axial displacement of the axle shaft in an outboard direction. A cylindrical outer peripheral surface of the axle shaft terminal shoulder is provided with external helical threads engaging internal threads of the endplay adjustment member. The endplay adjustment member is selectively positioned on said terminal shoulder along the axial direction of said axle shaft to variably limit an axial movement of the retainer ring within the annular groove, thus adjusting the axle shaft endplay.
With this arrangement of the differential assembly, the method for adjusting an axle shaft endplay in a differential assembly is performed in the following manner: first, a value of a desired endplay is determined based on particular operational conditions and the type of the differential assembly. A differential mechanism is then partially assembled including side gears and the axle shafts one at a time inserted through the side gears where the retainer ring is mounted to the axle shaft and the endplay adjustment member is fully threaded onto the terminal shoulder thereof. The shaft is then pulled outboard until the retainer ring contacts with the side gear. Then a pinion shaft carrying bevel pinion gears is assembled and locked in place. After that, the axle shaft endplay is measured between an inboard contact face of the axle shaft and the pinion shaft. The endplay adjustment member is then rotated on the terminal shoulder so as to provide the desired endplay xcex4P. Finally, remaining components of the differential assembly are assembled, thus, completing the process of assembling the differential assembly. The same procedure is then repeated for the other axle.
Therefore, the present device and method for adjusting the endplay of the axle shaft solve the need for a solution to the problem of controlling the axle shaft endplay in the vehicular differential assemblies in a simple, efficient and inexpensive manner.
These and other structural and functional benefits of the present invention will become apparent from the following description and associated drawings.